Short answer: there is no solid evidence that a hippyflip is inherently better than MDMA or psilocybin alone. What feels most helpful varies by person, context, and goals, and I cannot verify claims that the combo gives better outcomes.
MDMA is often described as empathogenic and conversational, while psilocybin is typically more introspective and perceptual. Some people report a synergistic feel when combining, but mixing substances also adds unpredictability and raises the chance of unwanted effects.
Preparation, set and setting, and post-session integration often matter as much as the substance choice. If someone is unsure, exploring each substance separately with proper support and spacing may reduce variables.
For a concise overview of potential pros, cons, and open questions about combining, see this Q&A: Can you combine psilocybin with MDMA.
Hope this helps.